Electrical equipment and components are often mounted within various housings to protect them from potentially damaging environmental effects, such as the weather, and to protect individuals that come in close proximity to such electrical equipment from injury in the event of the catastrophic failure of such electrical equipment. Moreover, it is also typically required for such electrical equipment and components to be inspected periodically to ensure that their operational performance is within target specifications and defined operating parameters. Therefore, access to the electrical equipment and components within the housing to examine and analyze such equipment and components is necessary, while still providing the safety benefits to both the equipment and the individuals inspecting the equipment.
One approach for accomplishing such inspections of the electrical equipment and components mounted within the protective housing is to utilize various cameras or sensors that are sensitive to different spectral ranges of electromagnetic radiation or light. For example, a camera or detector sensitive to either infrared (IR) light, ultraviolet (UV) light, or visible light may be used to image the electrical equipment and components, in order to ensure that the electrical equipment and components are operating within their intended operating specifications. That is, by obtaining an image (thermal, ultraviolet, or visual) of the electrical equipment using such cameras, an inspector is able to identify specific areas of the electrical equipment or components that are failing or that are achieving temperatures that are hotter or cooler than their specified operating range. Such a monitoring process allows the inspector of such electrical equipment and components to readily identify and resolve any potential problems before they occur, as well as to troubleshoot any existing problems.
In order to provide access to the electrical equipment or components carried within the housing, a viewing window is disposed within the wall of the housing, which is transparent to either IR, UV, or visible light, so as to allow the corresponding camera to have a clear field of view (FOV) of the electrical equipment and components there within. In other words, in the case of an IR viewing window, it is formed of infrared (IR) transparent material; in the case of an ultraviolet (UV) viewing window, it is formed of ultraviolet (UV) transparent material; and in the case of a visible light viewing window, it is formed of material that is transparent to visible light and readily viewed by a human observer. As such, the selected IR, UV, or visible light viewing window allows the transmission of the corresponding electromagnetic spectral range to pass therethrough so that it can be imaged or otherwise monitored by the appropriate camera or detection device.
It is a typical practice in industry to retrofit existing housings with viewing windows. However, such a process requires specialized training, and a substantial amount of time to precisely identify the optimal location for placing the viewing window in the housing to maximize the viewing angle or field of view (FOV) of the camera or detector through the viewing window to obtain images of the most critical aspects of the electrical equipment and components that are carried therein. As such, due to the complexities involved, retrofitting the viewing window to an existing housing often leads to less than optimal results.
For example, typical bus ducts, such as iso-phase bus ducts, due to their cylindrical shape, are difficult to inspect, and require substantial modification in order to be retrofit with standard flat or planar infrared (IR) viewing windows. As such, this additional complication that cylindrical bus ducts and other curved housings cause during the retrofit process, increases the likelihood that an unsatisfactory result will be achieved when retrofitting a curved housing with a flat or planar IR viewing window. In one aspect, such unsatisfactory results may include unwanted environmental leakage around the interface of the bus duct and the IR viewing window, as well as unwanted intrusion of debris and other particles from the external environment through the interface into the housing.
Therefore, there is a need for a curved viewing window assembly for a curved housing, such as a cylindrical bus duct, that includes a curved lens assembly that is made integral with or retro fit to the curved housing to monitor electrical equipment and components mounted therein. Still yet, there is a need for a curved viewing window assembly for a curved housing, that includes a curved lens assembly that is transparent to infrared (IR), ultraviolet (UV), and/or visible light to monitor electric equipment and components mounted therein. In addition, there is a need for a curved viewing window assembly for a housing having an at least partially curved portion, such as a cylindrical bus duct, that has a curved door that can be opened and closed, so as to provide selective access to the curved lens assembly.